Method of making composite metal articles



March 23, 1937. P A E, ARMSTRONG '2,074,352

METHOD OF MAKING COMPOSITE METAL ARTICLES Filed July ll, 1936 y "wmwmm ZZ Jl L9 lNveN-roR d l Percy /1.E.Armsr0ng V/ ,@V 4 J mmmmmw W Z f ATTORNEYS tween the wide walls of theingot mold was about 24 inches, so that a cast layer about 8% inches thick was formed on each side of the assembly.

During the pouring, the outside protective mild steel plates did not appear to bow; neither did any of the welds let go. The molten steel was a -usual steel containing .17% carbon and aplpeared to lie against the plates Il without unduly cooling themolten metal. The electrolytic iron on the outside of the plates I4 did not peel olf at all. `Pouring the ingot took about 10 minutes. v

The ingot (which weighed about l2 tons) remained in the mold until it cooled down sufficiently to be solid, and was then taken over to the soaking pits and soaked at about 2250" F. for three hours, after which it was put on a large plate rolling mill and rolled down -until it was 10 inches thick, about 85 inches wide and about Y 102 .inches long. After the usual re-heating in the soaking pits the slab was rolled down'until it was about54l4 inches thick and approximately 130 inches wide-by 150 inches long. The slab was then trimmed on. the edges and the two composite plates readily separated.each being about 21A, inches thick. When fully trimmed down these plates were about 100 inches wide by 110 inches long.

Having the plates I4 definitely separated from the plates III had the double advantage of permitting plates I4 to heat rapidly so that they did not bulge and also prevented large amounts of heat being quickly drawn from these plates to the 'center of the assembly so as to chill the iron` during casting. Perhaps `Isome welding took place between the plates I0 and the plates I4 Vdue to the pressure occasioned by shrinkage of the metaL'but in any event a complete weld took place duringY the subsequent working, so that two composite plates of great strengtlrwere obtained. with the electrolytic iron diffused into both layers. rating the two finished plates, for the alloy steel had not bowed sumciently to permit the separating material to fall out of place.

Under some circumstances, it may be desirable to use the inventive idea here set forth in producing a single sheet of clad material. In that case, the problem of having the two plates of alloy steel bow apart does not exist, but nevertheless it may be worth while to enclo the alloy steel plate in a casing. Since it will obviously not be desirable to have the alloysteel welded to the casing members on both sides. separating materialshould be used on one side, but of course precautions must be taken to prevent this separating material from working between the faces that are to be welded. One way 0f doing this is illustrated ln Fig. 3,- in which II designates thehplate of alloy steel, I i one casing member separated from the alloy steel II by the separating material I3 and welded to the member II as indicated atA I1. Plate II, which may be for example of mildl steel, acts as one of the Also there was no trouble in sepacasing members and is preferably heldslightly spaced from the alloy plate I I by the nller blocks V2l. Both faces of member Il preferably are covbe packed with steel wool which will tend to prevent the separating material from working down between the plate II and the member Il, even if the weld I1 becomes sheared. The casting is done as above described and after rolling, when the edges are sheared. plate I5 will readily separate, whereas plate I9 will be firmly welded to plate II.

While this invention is primarily of benefit in connection with making composite metals when used in conjunction with the invention of my patent above referred to, it may under some circumstances, and working with particular types of inserts be used without the step of eleetroplating; for example, it may be advantageously used for making composite metal comprising a steel backing and nickel facings.

It is to be understood that the examples given are only by way of illustration and the details and types4 of metals employed may be widely modified' without departing from the spirit of my invention.

What I claim is:

1. The method of making composite metal articles which comprises attaching together two metal plates with a layer of Vseparating material between them, enclosing such assembly in a casing of ferrous metal which substantially entirely surrounds such assembly and encloses the same but is not substantially attached to the assembly members, arranging such 'casing in an ingot mold, pouring ferrous metal around the same, whereby the casing members are heated rapidly while the enclosed assembly is withdrawing relatively little heat from the casing by conduction, and thereafter subjecting the ingot to hot working. trimmingaand separating. 1

Y2. A method as specified in claim 1, in which ."t/he casing is made large enough to permit substantial movement of the assembly within the casing in the plane of the assembly plates.

3. i method asspecified in claim l, in which the assembly is substantially covered with elec- A- trolytic iron and the face members of the casing are covered with electrolytic iron both inside and outside. Y

4. A method of making composite metal articles which comprises enclosing a metal plate in a'casing of ferrous metal which substantially entirely surrounds such plate but is not at- `tached to such plate on one face, said plate having separating material covering its opposite face, arranging such casing in an ingot mold, pouring ferrous metal around the same whereby the casing members aeuheated rapidly while the enclosed plateis withdrawing relatively little heat from the casing by conduction, and thereafter subjecting the ingot to hot wor trimming and separating. whereby a sheet is ed having one face composed of the metal of said lplate and the other facecomposed of the cast ferrous metal with` metal of AAsaidcasing between PERCY` A. E. MHG.

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